Some people have issues binding widgets that extend this class with a model attribute, although the documentation is pretty clear.
So for the new ones out there if you have a model named 'Client' and you want to use a CJuiDatePicker for the attribute 'birthdate'

The reason is because this may work for create actions but will not have any use for the update or if there are errors in form. You will notice there will be no value there, because the widget does not where to take it from. The solution is simple and it's clear in the docs. It's the combination of the model & attribute properties of the CJuiInputWidget class. So for the above we must do